The present invention relates generally to protective sleeves for electrical wiring and hoses. In particular, the present invention is a self-sealing reflective sleeve that provides protection for wiring and hoses from excessive heat.
In, for example, an automobile engine compartment, there are various hoses and electrical wires that pass near the engine or near other heat generating components where they are exposed to heat during the operation of the vehicle. Heat has an adverse effect on the insulation on electrical wiring and tends to degrade it and can also interfere with operation long before the insulation fails. Likewise, automotive fluids and fluid handling conduits are quickly degraded and pose a safety risk if directly exposed to the high temperatures of components carrying engine exhaust.
The need for thermally insulated electrical wiring and hoses is not confined to the automobile industry. There are, in fact, many applications where electrical wiring and hoses traverse a thermally elevated environment where thermal insulation would assure longer, more reliable operation. Moreover, there are many environments where insulation from extreme cold would also insure longer, more reliable operation.
There are many types of sleeves that shield wiring and hoses from the effects of heat. Typically, these are composed of a series of layers including at least one that reflects heat. Because of the need for flexibility, either flexible material or structural features that permit flexing are incorporated into the design of these sleeves. A problem with these sleeves is in installation. Clearly, whenever possible, a sleeve should be slipped over the end of the wiring or tubing it is designed to protect and be moved axially into position. However, it is often more convenient to be able to wrap the sleeve over the wiring and cabling from the side. If the sleeve is slit lengthwise to accommodate installation from the side, the slit itself becomes a route through which heat can penetrate, especially when the sleeve is bent because of the formation of gaps along the slit.
There remains a need for a thermally insulating sleeve that has good flexibility in both the unflexed and flexed conditions.
According to its major aspects and briefly recited, the present invention is a self-sealing reflective sleeve for use in insulating electrical wiring, hoses and tubing from heat or cold and that includes an inner layer and an outer layer. The inner layer is comprised of a tube that, depending on the temperature of application, can made of nylon, polyethylene, polypropylene or any other suitable plastic. The outer layer, depending on the temperature of the application and the desired insulating properties, can be made of, for example, lightweight fiberglass fabric laminated to aluminum foil. The aluminum foil reflects heat while the fiberglass fabric resists thermal change thereby isolating the aluminum foil which acts as a heat sink. Different outer layers can be used where climactic conditions so dictate. For example, the fabric and foil can be varied in both thickness and material to adapt to the end-use conditions such as, heat, cold, flexing requirements, and the like. In alternate embodiments, metalized polyester films may be used as the outer covering material.
The self-sealing reflective sleeve of the present invention affords enhanced thermal protection as compared to conventional sleeves currently available. When using, for example, a self-sealing reflective sleeve according to the present invention made of fiberglass fabric and aluminum foil, the aluminum foil imparts high heat reflectivity while the fiberglass fabric provides an insulating factor under the aluminum foil thereby providing enhanced thermal protection for the hoses or electrical wiring inside.
Another benefit of the present invention, is that the self-sealing reflective sleeve enjoys excellent flexibility without gapping, and, therefore, does not hinder the flexibility of hoses, tubing and wiring to which it is applied.
Yet another benefit of the present invention is that it lacks the common problem in conventional sleeves of having a slit, namely, gapping. Even under extreme flexing, the seam of the self-sealing reflective sleeve of the present invention remains closed.
Yet another benefit of the self-sealing reflective sleeve of the present invention as compared to conventional sleeves is the maintenance of a continuous closure.
Yet another advantage of the self-sealing reflective sleeve of the preset invention is that it provides enhanced heat protection due to the presence of air pockets between the two layers.
Still another feature of the present invention is that the self-sealing reflective sleeve of the present invention is constructed by wrapping of the outer layer laminate over the longitudinal edges of the inner layer thereby providing a smooth edge rather than the saw-tooth edge of conventional convoluted sleeves. This feature is especially significant when the end-use application is on wire harnesses where there is great concern regarding insulation cut-through at the time of installation.
Other features and their advantages will be apparent to those skilled in automotive electronics or fluid handling from a careful reading of the Detailed Description of Preferred Embodiments, accompanied by the following drawings.